scholarly journals On the Influence of Fracture Criterion on Perforation of High-Strength Steel Plates Subjected to Armour Piercing Projectile

2015 ◽  
Vol 62 (2) ◽  
pp. 157-179 ◽  
Author(s):  
Djalel Eddine Tria ◽  
Radosław Trebinski
Keyword(s):  
Shear Stress ◽  
Fracture Criterion ◽  
Maximum Shear Stress ◽  
Equivalent Plastic Strain ◽  
Stress Triaxiality ◽  
High Strength ◽  
Steel Plates ◽  
Fracture Model ◽  
Simple Material ◽  
Shear Plugging

Abstract This paper presents a numerical investigation of fracture criterion influence on perforation of high-strength 30PM steel plates subjected to 7.62x51 mm Armour Piercing (AP) projectile. An evaluation of four ductile fracture models is performed to identify the most suitable fracture criterion. Included in the paper is the Modified Johnson-Cook (MJC) constitutive model coupled separately with one of these fracture criteria: the MJC fracture model, the Cockcroft-Latham (CL), the maximum shear stress and the constant failure strain models. A 3D explicit Lagrangian algorithm that includes both elements and particles, is used in this study to automatically convert distorted elements into meshless particles during the course of the computation. Numerical simulations are examined by comparing with the experimental results. The MJC fracture model formulated in the space of the stress triaxiality and the equivalent plastic strain to fracture were found capable of predicting the realistic fracture patterns and at the same time the correct projectile residual velocities. However, this study has shown that CL one parameter fracture criterion where only one simple material test is required for calibration is found to give good results as the MJC failure criterion. The maximum shear stress fracture criterion fails to capture the shear plugging failure and material fracture properties cannot be fully characterized with the constant fracture strain

A Stress-Based Model for Shear Ductile Fracture

2019 ◽  
Vol 794 ◽  
pp. 3-8
Author(s):  
Yan Shan Lou ◽  
Jeong Whan Yoon
Keyword(s):  
Shear Stress ◽  
Ductile Fracture ◽  
Fracture Stress ◽  
Maximum Shear Stress ◽  
Stress Triaxiality ◽  
Fracture Model ◽  
Deformation Effect ◽  
Lode Parameter ◽  
Fracture Locus ◽  
Lightweight Metals

A stress-based model is developed to describe shear ductile fracture of lightweight metals. The proposed function couples the effect of the maximum shear stress and the stress triaxiality on fracture limits of metals during plastic deformation. Effect of the maximum shear stress in the proposed fracture model is correlated with the influence of the Lode parameter on fracture limits. The proposed fracture model is applied to depict the fracture locus of AA2024-T351. The predicted fracture locus is compared with experimental results of the alloy. The comparison demonstrates that the proposed fracture model reasonably characterizes the fracture stress in various loading conditions of compression, shear and tension.

Burring Process and Fracture Criterion of Large Diameter Steel Pipe

2020 ◽  
Vol 846 ◽  
pp. 139-145
Author(s):  
Shinichi Nishida ◽  
Daichi Uematsu ◽  
Naoki Ikeda ◽  
Kyohei Ogawa ◽  
Makoto Hagiwara ◽  
...  
Keyword(s):  
Shear Stress ◽  
Fracture Criterion ◽  
Maximum Shear Stress ◽  
Large Diameter ◽  
Branch Pipe ◽  
Fem Analysis ◽  
Equivalent Strain ◽  
Steel Pipe ◽  
Experimental Result ◽  
Forming Limit

This paper describes finite element method analysis (FEM analysis), results of burring processing of large diameter steel pipe and fracture criterion in burring process of large diameter steel pipe. In this study, the pipe is the 150A SGP pipe with a diameter of 165.2 mm and a wall thickness of 5 mm. The pipe is used for a plant as a flow channel of gas and liquid. A burring process of pipe is generally for forming the branch. The burring process is achieved by drawing of die from prepared hole. And the branch pipe is welded to the formed pipe. This process has some problem. One is the forming limit of pipe, and the other is needed to machining the end surface to be welded. Therefore, in this study, the forming limit of SGP pipe was estimated by FEM analysis of burring process. The parameters used for criteria for forming limit are the maximum shear stress and the equivalent strain. As a result of comparing the analysis result and the experimental result, the forming limit of the 150A SGP pipe was estimated that the maximum shear stress is 350 MPa and the equivalent strain is around 0.8.

scholarly journals Experimental and Numerical Study on the Protective Behavior of Weldox 900 E Steel Plates Impacted by Blunt-Nosed Projectiles

Metals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 141
Author(s):  
Yahui Shi ◽  
Ang Hu ◽  
Taisheng Du ◽  
Xinke Xiao ◽  
Bin Jia
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Fracture Criterion ◽  
Numerical Study ◽  
Mesh Size ◽  
High Strength ◽  
Element Model ◽  
Steel Plates ◽  
Protective Behavior ◽  
The Finite Element Model

To demonstrate the importance of incorporating Lode angle into fracture criterion in predicting the penetration resistance of high-strength steel plates, ballistic tests of blunt-nosed projectiles with a diameter of 5.95 mm impacted 4 mm thick Weldox 900 E steel plates were conducted. Impacting velocity range was 136.63~381.42 m/s. The fracture behavior and the ballistic limit velocities (BLVs) were obtained by fitting the initial-residual velocities of the projectiles. Subsequently, axisymmetric finite element (FE) models parallel to the tests were built by using Abaqus/Explicit software, and the Lode-independent Johnson–Cook (JC) and the Lode-dependent ASCE fracture criterion were incorporated into the finite element model for numerical simulation. Meanwhile, to verify the sensitivity of the mesh size in the numerical simulation, different mesh sizes were used in the shear plug area of the target. It can be found that Weldox 900 E steel has obvious mesh size sensitivity by comparing the experimental results and numerical simulation, and the JC fracture criterion and the ASCE fracture criterion predicted similar BLV for the same mesh size.

scholarly journals Ductile Fracture Behavior of Mild and High-Tensile Strength Shipbuilding Steels

2020 ◽  
Vol 10 (20) ◽  
pp. 7034
Author(s):  
Burak Can Cerik ◽  
Joonmo Choung
Keyword(s):  
Tensile Strength ◽  
Stress State ◽  
Ductile Fracture ◽  
Fracture Behavior ◽  
Maximum Shear Stress ◽  
Stress Triaxiality ◽  
Fracture Model ◽  
Loading Path ◽  
Alternative Form ◽  
High Tensile Strength

A comparison is made of the ductility limits of one mild (normal) and two high-tensile strength shipbuilding steels with an emphasis on stress state and loading path dependency. To describe the ductile fracture behavior of the considered steels accurately, an alternative form of ductile fracture prediction model is presented and calibrated. The present fracture model combines the normalized Cockcroft–Latham and maximum shear stress criterion, and is dependent on both stress triaxiality and Lode angle parameter. The calibrations indicate that, depending on the hardening characteristics of the steels, ductile fracture behavior differs considerably with stress state. It is demonstrated that the adopted fracture model is able to predict the ductile fracture initiation in various test specimens with good accuracy and is flexible in addressing the observed differences in the ductile fracture behavior of the considered steel grades.

scholarly journals Analysis of Fracture Behaviour of Exploded Metal Cylinders with Varied Charge

2018 ◽  
Vol 183 ◽  
pp. 01036 ◽  
Author(s):  
Xinlong Dong ◽  
Xinlu Yu ◽  
Shunjie Pan
Keyword(s):  
Shock Wave ◽  
Shear Stress ◽  
Shear Fracture ◽  
Maximum Shear Stress ◽  
Equivalent Plastic Strain ◽  
Outer Wall ◽  
Detonation Pressure ◽  
Element Analysis ◽  
Free Expansion ◽  
Metal Cylinder

Explosively driven fragmentation of ductile metals cylinders is a highly complex phenomenon. In this work, the fracture characteristics of exploded TA2 titanium alloy cylinder with varied charge were investigated numerically and experimentally. The results show that the fracture surfaces of fragments lie along planes of maximum shear stress for either a higher or a lower detonation pressure, but their mechanism is different. The finite element analysis demonstrated that the equivalent plastic strain in the middle of the wall is always larger than that of inner and outer wall for metal cylinder during the stage of shock wave driven period. For the high explosive pressures, the micro-cracks originated firstly in middle zone of wall during the stage of shock wave driven, and extend to the inner and outer wall in the direction of maximum shear stress. Explosives which generate lower detonation pressures, the shear fracture of cylinder originated from the inner wall and propagate to the outer wall in an angle of 45° or 135° to radial, the crack begin at the stage of free expansion. The simulated analysis of the process of deformation and fragmentation for exploded metal cylinder agree with the experimental results.

scholarly journals Lode Parameter Dependence and Quasi-Unilateral Effects in Continuum Damage Mechanics: Models and Applications in Metal Forming

2015 ◽  
Vol 651-653 ◽  
pp. 187-192
Author(s):  
Celal Soyarslan ◽  
Helmut Richter ◽  
Swantje Bargmann
Keyword(s):  
Shear Stress ◽  
Damage Mechanics ◽  
Maximum Shear Stress ◽  
Stress Triaxiality ◽  
Parameter Dependence ◽  
Punch Force ◽  
Lode Parameter ◽  
Principal Axes ◽  
Strain Paths ◽  
Stress Dependent

This work concerns with two successive modifications of the Lemaitre's damage model tomeet the requirements of formability prediction for today's modern steels. The first one is the quasiunilateraldamage evolution which modifies the damage driving force by scaling the elastic energyrelease rate due to compressive principal stress components. The second one is the shear modificationby which the damage rate is multiplied by a normalized maximum shear stress dependent factor.With the assumption of non-rotating principal axes of deformation, proportional strain paths and rigidplasticity, closed form expressions for the isochronous fracture surfaces are derived for each modelvariant and resulting surface plots at various spaces are compared. The findings show that the formermodification not only remedies the pathological reflective symmetry of the fracture surface acrossthe plane with vanishing stress triaxiality ratio, but also allows hindering fracture under uniaxialcompression. The latter modification by adding a direct Lode parameter dependence to the damageevolution function allows prediction of premature fracture at generalized shear stress states, a conditionobserved for certain advanced high strength metallic sheets. Parameter calibration is realized foreach model variant using the experimental data from the literature. It is shown that the fracture modelwith both the shear modification and the quasi-unilateral enhancement shows the best fitting quality.Finally, the models are implemented as user subroutines for ABAQUS/EXPLICIT and used in predictionof initiation and propagation of cracks for a series of deep-drawing punch tests. A good agreementwith the outputs reported in the literature is observed in terms of the shear damage occurrence zonesas well as corresponding punch force-displacement diagrams.

Sign in / Sign up

Export Citation Format

Share Document